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Achieving independent control of phase and amplitude is pivotal yet challenging for electromagnetic (EM) wave manipulation. Metasurface provides an efficient recipe to this challenge, but most of the work reports so far are still confined in half space (transmission or reflection) and manipulation of linearly polarized EM waves, restricting itself from integrating more functionalities with complex wavefronts into one optoelectronic device. Here, a hybrid phase approach synthesizing propagation and geometric phases is proposed to achieve independent and arbitrary control of amplitude and phase response for circularly polarized (CP) wave in full space by using a non‐interleaved single‐celled metasurface. To validate the concept, a full‐space dual‐channel meta‐hologram is experimentally demonstrated, manifesting images of letters "T" and "R" at lower and upper frequencies (f1 and f2), respectively. The finding of full‐space metasurface opens new possibilities to control CP waves by simultaneous amplitude and phase modulations, which is important for high‐capacity wireless communications, as well as sophisticated functionality, and other advanced meta‐devices. [ABSTRACT FROM AUTHOR]

Metasurface radome is crucial to protect the radiating antenna and control electromagnetic waves flexibly. However, current design methods for metasurface radome merely focus on the single propagation direction, with limited degrees of freedom. Here, a super radome is proposed with a directional scattering response based on Janus metasurface that can realize the phase modulation of y‐polarized waves and the amplitude modulation of x‐polarized waves with a judiciously designed structure. Both numerical and experimental results illustrate two cross‐polarized transmission windows with intensity exceeding 0.9 centered at 10 and 12.2 GHz and two out‐of‐band invisibility with considerable backward radar cross‐section reduction over −10 dB within 9.3–15.4 and 7.5–23.8 GHz when the radome is illuminated by y‐ and x‐polarized waves along negative and positive z directions, respectively. Moreover, the radar cross‐section reduction is maintained for off‐normal incidence even up to 45°. This method sets up a directional degree of freedom for advanced radome design and demonstrates its enormous potential in developing next‐generation stealth antennas. [ABSTRACT FROM AUTHOR]

Simultaneously independent control of phase, amplitude, and polarization is pivotal yet challenging for manipulating electromagnetic waves by transmissive metasurfaces. Huygens' metasurface affords a high‐efficiency recipe primarily by engineering phase‐only meta‐atoms, restricting itself from realizing unprecedentedly complex functions of the transmission beam. Here, a 3D chirality‐assisted metasurface concept relying on integrated magnetoelectric meta‐atoms is proposed. It empowers the completely decoupled and arbitrary control of phase and amplitude at large incident angles and arbitrary polarizations. This strategy thus facilitates very sophisticated beam manipulations at close‐to‐unity cross‐polarized efficiency via trilayer integrated resonators with mutual twist. The prescribed phase coverage can be determined by geometrical footprints of the unit cell, while the global azimuthal twist unlocks the capability of tuning amplitudes without affecting the phase. The concept and significance of it are validated to implement several proof‐of‐prototype demanding functionalities by thin metasurfaces of λo/12, which generate self‐accelerating diffraction‐free Airy beams, lateral and axial dual focusing, and even specific multiplexed beam shaping, respectively. This finding opens up an alternative way in very fine control of light with minimalist complexity and advanced performance. It can stimulate novel and high‐performance versatile photonic metadevices, thanks to the fully independent control of phase, amplitude, and polarization. The decoupling of amplitude, phase and polarization is analogous to the mechanical counterpart of three‐gear systems. The traditional dilemma is that tuning of either part will automatically affect the rest. This locks up metasurface functions and thereby limits its potentials. Now the authors' concept unlocks those "gears" such that each could be independently tuned, providing unprecedented access to the flatland of high‐efficiency metasurfaces. [ABSTRACT FROM AUTHOR]